N-Dimethylbenzylacetamide derivatives, and their production and use

ABSTRACT

A compound of the formula: ##STR1## wherein X is a hydrogen atom, a methyl group, a methoxy group or a chlorine atom, R 1  is a C 2  -C 7  alkyl group or a C 5  -C 7  cycloalkyl group and R 2  is a hydrogen atom, a halogen atom, a C 1  -C 4  alkyl group or a methoxy group, or when R 1  and R 2  are taken together, they represent a C 4  -C 6  alkylene group, provided that when R 1  is a tertiary alkyl group, R 2  does not represent a halogen atom, herbicidal compositions containing the above-mentioned compounds and methods for controlling weeds utilizing the same.

The present invention relates to N-dimethylbenzylacetamide derivatives,and their production and use. More particularly, it relates toN-dimethylbenzylacetamide derivatives and herbicidal compositionscontaining the same, and their preparation processes.

The said N-dimethylbenzylacetamide derivatives are representable by theformula (I): ##STR2## wherein X is a hydrogen atom, a methyl group, amethoxy group or a chlorine atom, R₁ is a C₂ -C₇ alkyl group or a C₅ -C₇cycloalkyl group and R₂ is a hydrogen atom, a halogen atom, a C₁ -C₄alkyl group or a methoxy group, or when R₁ and R₂ are taken together,they represent a C₄ -C₆ alkylene group, provided that when R₁ is atertiary alkyl group, R₂ does not represent a halogen atom.

The term "halogen atom" as hereinabove used is intended to meanchlorine, bromine, fluorine and iodine, inclusively.

As the result of an extensive study, it has been found that theN-dimethylbenzylacetamide derivatives (I) have a strong herbicidalactivity against a wide variety of weeds. For instance, they can exert anotable controlling or eradicating activity on the following annual andperennial weeds by pre-emergence soil treatment or post-emergence foliaror soil treatments: Gramineae weeds such as barnyard-grass (Echinochloacrus-galli), large crabgrass (Digitaria sanguinalis), green foxtail(Setaria viridis), Cyperaceae weeds such as yellow nutsedge (Cyperusesculentus), nutsedge sp. (Cyperus difformis), purple nutsedge (Cyperusrotundus), Scirpus Hotarui, slender spikerush (Eleocharis acicularis),Cyperus serotinus and Eleocharis kuroguwai, Amaranthaceae weeds such asredroot pigweed (Amaranthus retroflexus), Chenopodiaceae weeds such ascommon lambsquarters (Chenopodium album), Polygonaceae such asladysthumb (Polygonum persicaria) and curlydock (Rumex japonicus),Pontederiaceae such as Monochoria vaginalis, Scrophulariaceae such asfalse pimpernel (Lindernia pyxidaria), Alismataceae such as arrowhead(Sagittaria pygmaea), Compositae such as dandelion (Taraxacumofficinale), Oxalidaceae such as Woodsorrel (Oxalis corniculata), etc.Thus, their herbicidal activity is effective in controlling anderadicating not only field weeds but also paddy field weeds.

Advantageously, the N-dimethylbenzylacetamide derivatives (I) do notproduce any injury on various crop plants such as rice, soybean, cotton,corn, peanut, sunflower, rape and potato and numerous vegetables such aslettuce, cabbage, tomato, cucumber and carrot.

Accordingly, the N-dimethylbenzylacetamide derivatives (I) are useful asherbicides applicable for field crops and vegetables as well as paddyrice. They are also useful as herbicides to be employed for orchard,lawn, pasture, tea garden, mulberry field, rubber plantation, forest,etc.

Japanese Patent Publication (unexamined) No. 88228/1973 and U.S. Pat.No. 3,498,781 disclose some pivalic acid amide derivatives, which aresomewhat similar to the N-dimethylbenzylacetamide derivatives (I) inchemical structure and which have a herbicidal activity. However, theherbicidal activity of the N-dimethylbenzylacetamide derivatives (I) isgenerally more excellent than that of the pivalic acid amidederivatives. It is particularly notable that, in comparison with thepivalic acid amide derivatives, the N-dimethylbenzylacetamidederivatives (I) exert an extremely high herbicidal effect on annual andperennial weeds in paddy fields without any phytotoxicity on riceplants. Further, the N-dimethylbenzylacetamide derivatives (I) are quitecharacteristic in being highly effective for controlling or eradicatingperennial Cyperaceae weeds.

The N-dimethylbenzylacetamide derivatives (I) can be produced byreacting an acetic acid derivative of the formula (II): ##STR3## whereinR₁ and R₂ are each as defined above, or its reactive derivative with adimethylbenzylamine derivative of the formula (III): ##STR4## wherein Xis as defined above.

The acetic acid derivative (II) may be synthesized, for instance, by themethod as disclosed in Angew. Chem., 78, 932 (1966) and J.Chem.Soc.,1977, 694. The dimethylbenzylamine derivative (III) is obtainable, forinstance, by the method as disclosed in J.Am.Chem. Soc., 71, 3929(1949).

For the reaction, the acetic acid derivative (II) or its reactivederivative and the dimethylbenzylamine derivatives (III) may be used inan equivalent ratio of 0.4 to 1.5:1, preferably 0.5 to 1.1:1. Thereaction may be carried out in the presence or absence of an inertsolvent. Examples of the inert solvent are hydrocarbons (e.g. benzene,toluene, xylene), halogenated hydrocarbons (e.g. chlorobenzene,methylene chloride, chloroform, carbon tetrachloride), ethers (e.g.diisopropyl ether, tetrahydrofuran, dioxane), alcohols (e.g. methanol,ethanol, isopropanol), ketones (e.g. acetone, methylethylketone,methylisobutylketone), esters (e.g. ethyl acetate), nitriles (e.g.acetonitrile), dimethylsulfoxide, dimethylformamide, water, etc. Amongthem, particularly preferred is benzene. The reaction may be carried outwithin a wide range of temperature from the freezing point to theboiling point of the solvent, preferably from 0° C. to the boilingtemperature of the solvent. If necessary, cooling or heating may beadopted.

As the acetic acid derivative (II) or its reactive derivative, there maybe used free acid, acid anhydride, acid chloride, acid bromide, acidester, etc. Depending upon the kind of the reactive derivative, anappropriate reaction aid such as a condensing agent, a dehydratingagent, an acid-eliminating agent or a catalyst may be employed in thereaction. In case of the free acid, dicyclohexylcarbodiimide, phosphoruspentachloride, phosphorus trichloride, phosphorus tribromide, thionylchloride, sodium hydroxide, potassium hydroxide, sodium methoxide,sodium ethoxide, triethylamine, pyridine, quinoline, isoquinoline,N,N-dimethylaniline, N,N-diethylaniline, N-methylmorpholine, etc. areexamples of the reaction aid. In case of the acid chloride or acidbromide, sodium hydroxide, potassium hydroxide, sodium methoxide, sodiumethoxide, triethylamine, pyridine, quinoline, isoquinoline,N,N-dimethylaniline, N,N-diethylaniline, N-methylmorpholine, sodiumacetate, etc., preferably triethylamine, may be used as the reactionaid. When the reaction aid is employed, its amount may be from acatalytic amount to 1.5 equivalent, preferably from 0.95 to 1.1equivalent to the material to be eliminated from the starting compoundsas the result of the reaction.

The recovery of the reaction product from the reaction mixture may becarried out in a per se conventional manner. For instance, the reactionmixture is filtered and/or washed with water, followed by distillationfor removal of the solvent to give the reaction product, i.e. theN-dimethylbenzylacetamide derivative (I). When desired, this reactionproduct may be purified by a per se conventional procedure such asrecrystallization from an appropriate solvent such as benzene, toluene,n-hexane, methanol, ethanol, chloroform or methylisobutylketone.

Practical embodiments of the preparation of theN-dimethylbenzylacetamide derivatives (I) are illustratively shown inthe following examples.

EXAMPLE 1

Into a 200 ml four-necked flask, there were charged toluene (100 ml),α,α-dimethylbenzylamine (9 g) and pyridine (5.8 g), andα-methyl-tert-butylacetyl chloride (9.9 g) was dropwise added theretowhile stirring at room temperature. Stirring was continuted for 3 hours.The reaction mixture was washed with water to remove pyridinehydrochloride. After the toluene layer was dried over anhydrous sodiumsulfate, the solvent was distilled off under reduced pressure. Theobtained residue was recrystallized from ethanol to give 13.8 g ofN-(α,α-dimethylbenzyl)-α-methyl-tert-butylacetamide. M.P., 162.5°-163.5°C.

Elementary analysis:

Calcd.: C, 77.68%; H, 10.19%; N, 5.66%. Found: C, 77.82%; H, 10.36%; N,5.83%.

EXAMPLE 2

Into a 200 ml four necked flask, there were charged benzene (100 ml),α,α-dimethylbenzylamine (9 g) and triethylamine (7.4 g),tert-butylacethyl chloride (9.5 g) was dropwise added thereto whilestirring at room temperature. Stirring was continued for 3 hours. Thereaction mixture was washed with water to remove triethylaminehydrochloride. After the benzene layer was dried over anhydrous sodiumsulfate, the solvent was distilled off under reduced pressure. Theobtained residue was recrystallized from ethanol to give 13.5 g ofN-(α,α-dimethylbenzyl)-tert-butylacetamide. M.P., 159°-160.5° C.

Elementary analysis:

Calcd.: C, 77.21%; H, 9.93%; N. 6.00%. Found: C, 77.25%; H, 10.03%; N,6.01%.

EXAMPLE 3

(1) Into a 200 ml four necked flask, there were charged benzene (100ml), α,α-dimethylbenzylamine (9 g) and triethylamine (7.4 g), andα-bromo-isovaleryl chloride (13.3 g) was dropwise added thereto whilestirring at room temperature. Stirring was continued for 3 hours. Thereaction mixture was washed with water to remove triethylaminehydrochloride. After the benzene layer was dried over anhydrous sodiumsulfate, the solvent was distilled off under reduced pressure. Theobtained residue was recrystallized from ethanol to give 16.9 g ofN-(α,α-dimethylbenzyl)-α-bromo-isovaleramide. M.P., 128°-129.5° C.

Elementary analysis:

Calcd.: C, 56.39%; H, 6.76%; N, 4.70%; Br, 26.79%. Found: C, 56.21%; H,6.47%; N. 4.78%; Br, 26.82%.

(2) Into a 500 ml four-necked flask, there were chargedmethylisobutylketone (150 ml), α,α-dimethylbenzylamine (27.0 g) andtriethylamine (21.2 g), and α-bromo-isovaleryl chloride (40.0 g) wasdropwise added thereto while stirring at room temperature. Stirring wascontinued for 3 hours. After completion of the reaction, water (200 ml)was added thereto and the reaction mixture was gradually heated toremove methylisobutylketone, followed by cooling at room temperature.The precipitated crystals were filtered, washed with water, dried andrecrystallized from ethanol to giveN-(α,α-dimethylbenzyl)-α-bromo-isovaleramide (51.9 g).

In the same manner as above, there can be produced otherN-dimethylbenzylacetamide derivatives (I), of which some specificexamples will be shown in Table 1 but without any intention to limit thescope of the invention thereto:

                                      TABLE 1                                     __________________________________________________________________________     ##STR5##                                                                     Com-                   Melting                                                pound                  point                                                                              Elementary analysis (%)                           No. R.sub.1   R.sub.2                                                                           X    (°C.)                                                                           C  H  N  Halogen                              __________________________________________________________________________    1   i-C.sub.3 H.sub.7                                                                       H   H    97-99                                                                              Calcd.                                                                            76.67                                                                             9.65                                                                            6.39                                                                Found                                                                             76.58                                                                             9.82                                                                            6.45                                    2   i-C.sub.4 H.sub.9                                                                       H   H    80-81                                                                              Calcd.                                                                            77.21                                                                             9.93                                                                            6.00                                                                Found                                                                             77.20                                                                            10.09                                                                            5.97                                    3   s-C.sub.4 H.sub.9                                                                       H   H    78-79                                                                              Calcd.                                                                            77.21                                                                             9.93                                                                            6.00                                                                Found                                                                             77.27                                                                            10.07                                                                            5.99                                    4   t-C.sub.4 H.sub.9                                                                       H   H    159- Calcd.                                                                            77.21                                                                             9.93                                                                            6.00                                                           160.5                                                                              Found                                                                             77.25                                                                            10.03                                                                            6.01                                    5   t-C.sub.4 H.sub.9                                                                       H   4-CH.sub.3                                                                         170-172                                                                            Calcd.                                                                            77.68                                                                            10.19                                                                            5.66                                                                Found                                                                             77.77                                                                            10.20                                                                            5.39                                         ##STR6## H   H    91-92.5                                                                            Calcd. Found                                                                      78.11 77.99                                                                      10.41 10.52                                                                      5.36 5.39                               7                                                                                  ##STR7## H   H    113.5- 115                                                                         Calcd. Found                                                                      78.11 78.32                                                                      10.41 10.51                                                                      5.36 5.19                               8                                                                                  ##STR8## H   H    95-96                                                                              Calcd. Found                                                                      78.11 78.12                                                                      10.41 10.68                                                                      5.36 5.24                               9                                                                                  ##STR9## H   H    72-73                                                                              Calcd. Found                                                                      78.49 78.38                                                                      10.61 10.83                                                                      5.09 5.27                               10                                                                                 ##STR10##                                                                              H   H    121-122                                                                            Calcd. Found                                                                      78.32 78.44                                                                       9.45  9.51                                                                      5.71 5.63                               11                                                                                 ##STR11##                                                                              H   H    124-126                                                                            Calcd. Found                                                                      78.72 78.88                                                                       9.71  9.70                                                                      5.40 5.29                               12                                                                                 ##STR12##                                                                              H   H    126-127                                                                            Calcd. Found                                                                      78.72 78.94                                                                       9.71  9.92                                                                      5.40 5.54                               13                                                                                 ##STR13##                                                                              H   H    138-139                                                                            Calcd. Found                                                                      79.07 79.19                                                                       9.95  9.82                                                                      5.12  5.03                              14  n-C.sub.3 H.sub.7                                                                       CH.sub.3                                                                          H    93-95                                                                              Calcd.                                                                            77.21                                                                             9.93                                                                            6.00                                                                Found                                                                             77.28                                                                            10.15                                                                            5.99                                    15  i-C.sub.3 H.sub.7                                                                       CH.sub.3                                                                          H    89-91                                                                              Calcd.                                                                            77.21                                                                             9.93                                                                            6.00                                                                Found                                                                             77.33                                                                             9.87                                                                            6.12                                    16  i-C.sub.3 H.sub.7                                                                       i-C.sub.3 H.sub.7                                                                 H    106-109                                                                            Calcd.                                                                            78.11                                                                            10.41                                                                            5.36                                                                Found                                                                             78.22                                                                            10.53                                                                            5.10                                    17  n-C.sub.4 H.sub.9                                                                       C.sub.2 H.sub.5                                                                   H    117.5-                                                                             Calcd.                                                                            78.11                                                                            10.41                                                                            5.36                                                           119  Found                                                                             78.03                                                                            10.29                                                                            5.42                                    18  t-C.sub.4 H.sub.9                                                                       CH.sub.3                                                                          H    162.5-                                                                             Calcd.                                                                            77.68                                                                            10.19                                                                            5.66                                                           163.5                                                                              Found                                                                             77.82                                                                            10.36                                                                            5.83                                    19  t-C.sub.4 H.sub.9                                                                       CH.sub.3                                                                          2-CH.sub.3                                                                         145-147                                                                            Calcd.                                                                            78.11                                                                            10.41                                                                            5.36                                                                Found                                                                             78.03                                                                            10.61                                                                            5.43                                    20  t-C.sub.4 H.sub.9                                                                       CH.sub.3                                                                          3-CH.sub.3                                                                         134- Calcd.                                                                            78.11                                                                            10.41                                                                            5.36                                                           135.5                                                                              Found                                                                             78.15                                                                            10.65                                                                            5.40                                    21  t-C.sub.4 H.sub.9                                                                       CH.sub.3                                                                          4-CH.sub.3                                                                         177-179                                                                            Calcd.                                                                            78.11                                                                            10.41                                                                            5.36                                                                Found                                                                             78.23                                                                            10.49                                                                            5.20                                    22  t-C.sub.4 H.sub.9                                                                       CH.sub.3                                                                          4-Cl 175- Calcd.                                                                            68.19                                                                             8.58                                                                            4.97                                                                             12.58 (Cl)                                                  177.5                                                                              Found                                                                             68.30                                                                             8.42                                                                            4.75                                                                             12.61 (Cl)                           23  t-C.sub.4 H.sub.9                                                                       C.sub.2 H.sub.5                                                                   H    169.5-                                                                             Calcd.                                                                            78.11                                                                            10.41                                                                            5.36                                                           170.5                                                                              Found                                                                             78.32                                                                            10.45                                                                            5.36                                    24  t-C.sub.4 H.sub.9                                                                       C.sub.2 H.sub.5                                                                   4-CH.sub.3                                                                         160-161                                                                            Calcd.                                                                            78.49                                                                            10.61                                                                            5.09                                                                Found                                                                             78.61                                                                            10.77                                                                            5.01                                    25  t-C.sub.4 H.sub.9                                                                       n-C.sub.3 H.sub.7                                                                 H    131- Calcd.                                                                            78.49                                                                            10.61                                                                            5.09                                                           132.5                                                                              Found                                                                             78.56                                                                            10.54                                                                            5.23                                    26  t-C.sub.4 H.sub.9                                                                       i-C.sub.4 H.sub.9                                                                 H    132- Calcd.                                                                            78.84                                                                            10.79                                                                            4.84                                                           133.5                                                                              Found                                                                             78.96                                                                            10.87                                                                            4.65                                    27  t-C.sub.4 H.sub.9                                                                       OCH.sub.3                                                                         H    95-97                                                                              Calcd.                                                                            72.97                                                                             9.57                                                                            5.32                                                                Found                                                                             72.71                                                                             9.64                                                                            5.06                                    28  C.sub.2 H.sub.5                                                                         Cl  H    109-110                                                                            Calcd.                                                                            65.13                                                                             7.57                                                                            5.84                                                                             14.79 (Cl)                                                       Found                                                                             65.32                                                                             7.75                                                                            5.90                                                                             14.97 (Cl)                           29  n-C.sub.3 H.sub.7                                                                       Br  H    111.5-                                                                             Calcd.                                                                            56.39                                                                             6.76                                                                            4.70                                                                             26.79 (Br)                                                  113.5                                                                              Found                                                                             56.42                                                                             6.91                                                                            4.77                                                                             26.84 (Br)                           30  i-C.sub.3 H.sub.7                                                                       Br  H    128- Calcd.                                                                            56.39                                                                             6.76                                                                            4.70                                                                             26.79 (Br)                                                  129.5                                                                              Found                                                                             56.21                                                                             6.47                                                                            4.78                                                                             26.82 (Br)                           31  i-C.sub.3 H.sub.7                                                                       Br  2-OCH.sub.3                                                                        89-91                                                                              Calcd.                                                                            54.89                                                                             6.76                                                                            4.27                                                                             24.34 (Br)                                                       Found                                                                             54.75                                                                             6.80                                                                            4.33                                                                             24.49 (Br)                           32  i-C.sub.3 H.sub.7                                                                       Br  3-CH.sub.3                                                                         105-107                                                                            Calcd.                                                                            57.70                                                                             7.10                                                                            4.49                                                                             25.59 (Br)                                                       Found                                                                             57.59                                                                             7.21                                                                            4.38                                                                             25.63 (Br)                           33  i-C.sub.3 H.sub.7                                                                       I   H    147-149                                                                            Calcd.                                                                            48.71                                                                             5.84                                                                            4.06                                                                             36.76 (I)                                                        Found                                                                             48.79                                                                             5.93                                                                            3.84                                                                             36.92 (I)                            34  n-C.sub.4 H.sub.9                                                                       Br  H    90-91.5                                                                            Calcd.                                                                            57.70                                                                             7.10                                                                            4.49                                                                             25.59 (Br)                                                       Found                                                                             57.86                                                                             7.28                                                                            4.64                                                                             25.46 (Br)                           35  s-C.sub.4 H.sub.9                                                                       Br  H    99.5-                                                                              Calcd.                                                                            57.70                                                                             7.10                                                                            4.49                                                                             25.59 (Br)                                                  101  Found                                                                             57.90                                                                             7.24                                                                            4.58                                                                             25.55 (Br)                           36  s-C.sub.4 H.sub.9                                                                       Br  4-CH.sub.3                                                                         108- Calcd.                                                                            58.90                                                                             7.41                                                                            4.29                                                                             24.49 (Br)                                                  109.5                                                                              Found                                                                             59.11                                                                             7.63                                                                            4.14                                                                             24.37 (Br)                           37                                                                                 ##STR14##                                                                              Br  H    146.5- 148                                                                         Calcd. Found                                                                      59.27 59.38                                                                       6.84  6.65                                                                      4.32 4.19                                                                        24.64 (Br) 24.61 (Br)                38                                                                                 ##STR15##                                                                              Br  H    146- 147.5                                                                         Calcd. Found                                                                      60.36 60.18                                                                       7.15  7.09                                                                      4.14 4.30                                                                        23.62 (Br) 23.58 (Br)                39  (CH.sub.2).sub.4                                                                            H    134-135                                                                            Calcd.                                                                            77.88                                                                             9.15                                                                            6.05                                                                Found                                                                             77.81                                                                             9.34                                                                            5.93                                    40  (CH.sub.2).sub.5                                                                            H    158-159                                                                            Calcd.                                                                            78.32                                                                             9.45                                                                            5.71                                                                Found                                                                             78.53                                                                             9.57                                                                            5.52                                    41  (CH.sub.2).sub.6                                                                            H    176- Calcd.                                                                            78.72                                                                             9.91                                                                            5.40                                                           177.5                                                                              Found                                                                             78.94                                                                             9.82                                                                            5.34                                    __________________________________________________________________________

In the practical usage of the N-dimethylbenzylacetamide derivatives (I),they may be applied as such or in any preparation form such as granules,fine granules, dusts, coarse dusts, wettable powders, emulsifiableconcentrates, flowable formulations, aqueous concentrates or oilysuspensions.

In producing such preparation form, solid or liquid carriers may beused. As for the solid carrier, there may be given mineral powders (e.g.kaolin, bentonite, clay, montmorillonite, talc, diatomaceous earth,mica, vermiculite, gypsum, calcium carbonate, apatite), vegetablepowders (e.g. soybean powder, flour, wooden powder, tobacco powder,starch, crystalline cellulose), high molecular weight compounds (e.g.petroleum resin, polyvinyl chloride, dammar gum, ketone resin), alumina,wax and the like.

As for the liquid carrier, there may be given kerosene, alcohols (e.g.methanol, ethanol, ethylene glycol, benzyl alcohol), aromatichydrocarbons (e.g. toluene, benzene, xylene, methylnaphthalene),halogenated hydrocarbons (e.g. chloroform, carbon tetrachloride,monochlorobenzene), ethers (e.g. dioxane, tetrahydrofuran), ketones(e.g. acetone, methylethylketone, cyclohexanone, isophorone), esters(e.g. ethyl acetate, butyl acetate, ethylene glycol acetate), acidamides (e.g. dimethylformamide), nitriles (e.g. acetonitrile), etheralcohols (e.g. ethylene glycol ethyl ether), water and the like.

A surface active agent used for emulsification, dispersion or spreadingmay be any of the non-ionic, anionic, cationic and amphoteric type ofagents. Examples of the surface active agent include polyoxyethylenealkyl ethers, polyoxyethylene alkylaryl ethers, polyoxyethylene fattyacid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fattyacid esters, oxyethylene-oxypropylene polymers, polyoxyethylene alkylphosphates, fatty acid salts, alkyl sulfates, alkyl sulfonates,alkylaryl sulfonates, alkyl phosphates, polyoxyethylene alkyl sulfates,quaternary ammonium salts and the like. But, the surface active agent isnot of course limited to these compounds. And, if necessary, gelatin,casein, sodium alginate, starch, agar, polyvinyl alcohol or the like maybe used as an auxiliary agent.

In the preparation of a herbicidal composition, the content of theN-dimethylbenzylacetamide derivative (I) may be usually from 0.05 to 95%by weight, preferably from 3 to 50% by weight.

Practical embodiments of the herbicidal composition according to theinvention are illustratively shown in the following examples whereinparts and % are by weight.

PREPARATION EXAMPLE 1

Fifty parts of Compound No. 4, 2.5 parts of a dodecylbenzenesulfonate,2.5 parts of a ligninsulfonate and 45 parts of diatomaceous earth arewell mixed while being powdered to obtain a wettable powder.

PREPARATION EXAMPLE 2

Thirty parts of Compound No. 16, 10 parts of emulsifier ("Sorpol SM-100"manufactured by Toho Chemical Co., Ltd.) and 60 parts of xylene are wellmixed to obtain an emulsifiable concentrate.

PREPARATION EXAMPLE 3

Five parts of Compound No. 23, 1 part of white carbon, 5 parts of aligninsulfonate and 89 parts of clay are well mixed while beingpowdered. The mixture is then well kneaded with water, granulated anddried to obtain a granule.

PREPARATION EXAMPLE 4

Thirty parts of Compound No. 30, 1 part of isopropyl phosphate, 66 partsof clay and 30 parts of talc are well mixed while being powdered. Themixture is then kneaded with water, granulated and dried to obtain agranule.

PREPARATION EXAMPLE 5

Fourty parts of bentonite, 5 parts of a ligninsulfonate and 55 parts ofclay are well mixed while being powdered. The mixture is then wellkneaded with water, granulated and dried to obtain a granule containingno active ingredient. The granule is then impregnated with 5 parts ofCompound No. 35 dissolved in acetone. Subsequent removal of acetonegives a granule.

PREPARATION EXAMPLE 6

Ninety-five parts of bentonite of 16-48 mesh is impregnated with 5 partsof Compound No. 38 dissolved in acetone. Subsequent removal of acetonegives a granule.

The N-dimethylbenzylacetamide derivative (I) may be used together withother herbicides to improve their activity as herbicides, and in somecases, a synergistic effect may be expected. As the herbicides to bemixed with, there may be given phenoxy series herbicides such as2,4-dichlorophenoxyacetic acid, 2-methyl-4-chlorophenoxyacetic acid and2-methyl-4-chlorophenoxybutyric acid (including esters and saltsthereof); benzoic acid series herbicides such as3,6-dichloro-2-methoxybenzoic acid and 2,5-dichloro-3-aminobenzoic acid;diphenyl ether series herbicides such as2,4-dichlorophenyl-4'-nitrophenyl ether,2,4,6-trichlorophenyl-4'-nitrophenyl ether,2-chloro-4-trifluoromethylphenyl-3'-ethoxy-4'-nitrophenyl ether,2,4-dichlorophenyl-4'-nitro-3'-methoxyphenyl ether,2,4-dichlorophenyl-3'-methoxycarbonyl-4'-nitrophenyl ether and sodium5-(2'-chloro-4'-trifluoromethylphenoxy)-2-nitrobenzoate; triazine seriesherbicides such as 2-chloro-4,6-bisethylamino-1,3,5-triazine,2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine,2-methylthio-4,6-bisethylamino-1,3,5-triazine,2-methylthio-4,6-bisisopropylamino-1,3,5-triazone and4-amino-6-tert-butyl-3-methylthio-1,2,4-triazine-5-one; urea seriesherbicides such as 3-(3,4-dichlorophenyl)-1,1-dimethylurea,3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea,1-(2,2-dimethylbenzyl)-3-p-tolylurea and1-(2,2-dimethylbenzyl)-3-methyl-3-phenylurea; carbamate seriesherbicides such as isopropyl-N-(3-chlorophenyl)carbamate andmethyl-N-(3,4-dichlorophenyl)carbamate; thiolcarbamate series herbicidessuch as S-ethyl-N,N-dipropylthiolcarbamate,S-(4-chlorobenzyl)-N,N-diethylthiolcarbamate,S-ethyl-N,N-hexamethylenethiolcarbamate,S-2,3-dichloroallyl-N,N-diisopropylthiolcarbamate andS-ethyl-N,N-dibutylthiolcarbamate; acid anilide series herbicides suchas 3,4-dichloropropionanilide,N-methoxymethyl-2,6-diethyl-α-chloroacetanilide,2-chloro-2',6'-diethyl-N-butoxymethylacetanilide,2-chloro-2',6'-diethyl-N-(n-propoxyethyl)acetanilide andN-chloroacetyl-N-(2,6-diethylphenyl)glycineethyl ester; uracil seriesherbicides such as 5-bromo-3-sec-butyl-6-methyluracil and3-cyclohexyl-5,6-trimethyleneuracil; pyridinium chloride seriesherbicides such as 1,1'-dimethyl-4,4'-bispyridinium chloride; phosphorusseries herbicides such as N-(phosphonomethyl)glycine,O-ethyl-O-(2-nitro-5-methylphenyl)-N-sec-butylphosphoroamidothioate,S-(2-methyl-1-piperidylcarbonylmethyl) O,O-di-n-propyldithiophosphateand S-(2-methyl-1-piperidylcarbonylmethyl), O,O-diphenyldithiophosphate;toluidine series herbicides such asα,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine; aliphaticcompounds series herbicides such as trichloroacetic acid,2,2-dichloropropionic acid and 2,2,3,3-tetrafluoropropionic acid;5-tert-butyl-3-(2,4-dichloro-5-isopropoxyphenyl)-1,3,4-oxadiazolin-2-one;3-isopropyl-1H-2,1,3-benzothiadiazin (4)-3H-one-2,2-dioxide;2,6-dichlorobenzonitrile; α-(β-naphthoxy)propionanilide;4'-(phenylsulfonyl)-(1,1,1-trifluoromethylsulphono)-O-toluidide;4-(2,4-dichlorobenzoyl)-1,3-dimethylpyrazole-5-yl-p-toluenesulfonate;N-p-chlorobenzyloxyphenyl-Δ'-tetrahydrophthalimide and the like. But,the herbicides are not of course limited to these examples.

The herbicides of the invention may be applied together with fungicides,pyrethroid series insecticides, other insecticides, plant growthregulators, fertilizers, etc.

When the N-dimethylbenzylacetamide derivative (I) is used as aherbicide, it may be applied before or after germination of weeds in anamount within a wide range. The amount may be usually from about 0.1 to1 kilogram per hectare, preferably from about 0.25 to 5 kilograms perhectare.

Some test examples which show the herbicidal activity of theN-dimethylbenzylacetamide derivatives (I) are shown in the followingExamples wherein % is by weight.

EXAMPLE I

A Wagner's pot of 14 cm in diameter was filled with 1.5 kg of paddyfield soil and added with water to make paddy field conditions. Riceseedlings of 3-leaf growth stage were transplanted in the pot, and seedsof barnyard grass (Echinochloa cruss-galli) and Scirpus Hotarui, andbuds of slender spikerush (Eleocharis aciculalis), which tided over thewinter, were further sowed therein. A required amount of each testcompound was applied to the soil under water-lodged condition.Twenty-five days after the application, the herbicidal activity andphytotoxicity of the test compound were checked on the transplanted andsowed plants and spontaneously germinated Monochoria vaginalis. Theresults are shown in Table 2.

As to the application, a wettable powder containing a required amount ofthe test compound was diluted with water and applied in a proportion of10 ml/pot by means of a pipette. The herbicidal activity was evaluatedin figures ranging from 0 to 5.

    ______________________________________                                        Figures    Percentage of inhibition (%)                                       ______________________________________                                        0          0-9                                                                1          10-29                                                              2          30-49                                                              3          50-69                                                              4          70-89                                                              5           90-100                                                            ______________________________________                                    

As to the evaluation of phytotoxicity, the three factors (i.e. height ofplant, number of tillers and total weight (dry weight)) were eachchecked, and a ratio of the treated plot to the untreated plot wascalculated for each factor. The phytotoxicity was evaluated based on thelowest value of the three ratios which was classified into the followinggrades ranging from 0 to 5.

    ______________________________________                                        Grade      Ratio of the untreated plot (%)                                    ______________________________________                                        0          100                                                                1          90-99                                                              2          80-89                                                              3          60-79                                                              4          40-59                                                              5          0-39                                                               ______________________________________                                    

                  TABLE 2                                                         ______________________________________                                        Dosage                                                                        (weight    Herbicidal activity                                                      of ac-           Mono-               Phyto-                             Com-  tive in- Barn-   choria              toxicity                           pound gredient,                                                                              yard    vagin-                                                                              Scirpus                                                                              Slender                                                                              Rice                               No.   g/are)   grass   alis  Hotarui                                                                              spikerush                                                                            plant                              ______________________________________                                        1     40       5       5     5      5      0                                        20       3       5     4      5      0                                  2     40       5       4     5      5      0                                        20       3       4     4      4      0                                  3     80       --      5     5      5      0                                        40       --      4     5      5      0                                  4     40       5       5     5      5      0                                        20       5       5     5      5      0                                  5     40       --      5     5      5      0                                        20       --      4     5      5      0                                  6     40       5       5     5      5      0                                        20       5       4     5      5      0                                  7     20       5       5     5      5      0                                        10       4       4     5      5      0                                  8     20       5       5     5      5      0                                        10       4       4     5      4      0                                  9     20       5       5     5      5      0                                        10       4       4     5      5      0                                  10    40       5       4     5      5      0                                        20       4       4     4      5      0                                  11    40       --      4     5      5      0                                        20       --      4     5      4      0                                  12    40       5       5     5      5      0                                        20       4       5     5      5      0                                  13    40       5       5     5      5      0                                        20       5       4     5      5      0                                  14    20       4       4     5      5      0                                        10       3       4     4      5      0                                  15    20       5       5     5      5      0                                        10       5       4     5      5      0                                  16    20       5       5     5      5      0                                        10       5       5     5      5      0                                  17    40       5       5     5      5      0                                        20       5       5     5      5      0                                  18    20       5       5     5      5      0                                        10       5       5     5      5      0                                  19    40       5       5     5      5      0                                        20       5       4     5      5      0                                  20    40       5       5     5      5      0                                        20       5       5     5      4      0                                  21    40       5       5     5      5      0                                        20       4       5     5      5      0                                  22    40       5       5     5      5      0                                        20       5       4     5      5      0                                  23    80       --      5     5      5      0                                        40       --      4     5      5      0                                  24    80       --      5     5      5      0                                        40       --      5     5      5      0                                  25    80       --      5     5      5      0                                        40       --      5     5      5      0                                  26    80       --      5     5      5      0                                        40       --      4     5      4      0                                  27    80       --      4     5      5      0                                        40       --      4     4      5      0                                  28    40       5       5     5      5      0                                        20       4       4     5      5      0                                  29    80       5       5     5      5      0                                        40       4       5     5      4      0                                  30    40       5       5     5      5      0                                        20       5       5     5      5      0                                  31    40       5       4     5      5      0                                        20       5       4     5      5      0                                  32    40       5       5     5      5      0                                        20       5       5     5      5      0                                  33    40       5       5     5      5      0                                        20       4       4     5      5      0                                  34    20       5       5     5      5      0                                        10       5       5     5      5      0                                  35    20       5       5     5      5      0                                        10       5       5     5      4      0                                  36    40       --      5     5      5      0                                        20       --      4     5      5      0                                  37    80       5       5     5      5      0                                        40       5       5     5      5      0                                  38    20       5       5     5      5      0                                        10       4       4     5      5      0                                  39    40       5       5     5      5      0                                        20       4       5     5      5      0                                  40    40       5       5     5      5      0                                        20       4       5     5      5      0                                  41    20       5       5     5      5      0                                        10       5       4     5      5      0                                  Un-   --       0       0     0      0      0                                  treated                                                                       ______________________________________                                    

EXAMPLE II

The seeds of weeds such as large crabgrass (Digitaria sanguinalis),redroot pigweed (Amaranthus retroflexus), tubers of purple nutsedge(Cyperus rotundus) and seeds of crops such as peanut and cotton wereeach sowed in a 10 cm flower pot and covered with soil. Separately, arequired amount of each test compound was formulated into anemulsifiable concentrate and diluted with water. The diluted chemicalsolution was applied to the soil by means of a hand sprayer and the thustreated soil was mixed and kept to the depth of 2 cm from the soilsurface. Each of the weeds and crops was grown up in a green-house, andthe herbicidal activity and phytotoxicity of the test compound werechecked 20 days after the application. The test results are shown inTable 3. The herbicidal activity was evaluated in figures ranging from 0to 5. The phytotoxicity to the crop plants was also indicated on thesame standard as that of the herbicidal activity.

    ______________________________________                                        Figures    Percentage of inhibition (%)                                       ______________________________________                                        0          0-9                                                                1          10-29                                                              2          30-49                                                              3          50-69                                                              4          70-89                                                              5           90-100                                                            ______________________________________                                    

                  TABLE 3                                                         ______________________________________                                        Dosage                                                                        (weight                                                                       of ac-     Herbicidal activity                                                Com-  tive in-          Large                                                 pound gredient,                                                                              Purple   crab- Redroot                                                                               Phytotoxicity                           No.   g/are)   nutsedge grass pigweed                                                                              Peanut                                                                              Cotton                             ______________________________________                                         1    80       5        4     4      0     0                                        40       4        3     3      0     0                                   3    80       5        5     5      0     0                                        40       5        4     4      0     0                                   4    80       5        5     5      0     0                                        40       5        5     5      0     0                                   6    80       5        5     4      0     0                                        40       5        4     4      0     0                                   7    80       5        4     4      0     0                                        40       5        4     4      0     0                                   8    80       5        5     5      0     0                                        40       5        4     4      0     0                                   9    80       5        5     5      0     0                                        40       5        4     4      0     0                                  12    80       5        5     --     0     0                                        40       5        4     --     0     0                                  14    80       5        5     5      0     0                                        40       5        4     5      0     0                                  16    80       5        5     5      0     0                                        40       5        5     5      0     0                                  17    80       5        5     5      0     0                                        40       5        5     5      0     0                                  18    80       5        5     5      0     0                                        40       5        5     5      0     0                                        20       5        --    --     --    --                                       10       5        --    --     --    --                                 22    80       5        5     4      0     0                                        40       5        4     4      0     0                                  23    80       5        5     5      0     0                                        40       5        5     4      0     0                                        20       5        --    --     --    --                                       10       5        --    --     --    --                                 24    80       5        5     5      0     0                                        40       5        5     4      0     0                                        20       5        --    --     --    --                                       10       5        --    --     --    --                                 25    80       5        5     5      0     0                                        40       5        5     4      0     0                                        20       5        --    --     --    --                                       10       5        --    --     --    --                                 26    80       5        5     4      0     0                                        40       5        5     4      0     0                                  27    80       5        5     4      0     0                                        40       4        4     3      0     0                                  28    80       5        4     5      0     0                                        40       4        4     3      0     0                                  30    80       5        5     5      0     0                                        40       5        5     5      0     0                                  32    80       5        5     5      0     0                                        40       5        5     5      0     0                                  34    80       5        4     4      0     0                                        40       4        4     4      0     0                                  35    80       5        5     5      0     0                                        40       5        4     5      0     0                                  39    80       5        4     4      0     0                                        40       4        4     3      0     0                                  41    80       5        5     5      0     0                                        40       5        5     4      0     0                                  A*.sup.(1)                                                                          80       0        0     1      0     0                                        40       0        0     0      0     0                                  B*.sup.(2)                                                                          80       0        3     3      3     2                                        40       0        2     1      2     1                                  C*.sup.(3)                                                                          80       0        0     0      0     0                                        40       0        0     0      0     0                                  D*.sup.(4)                                                                          80       0        0     1      1     1                                        40       0        0     0      0     0                                  E*.sup.(5)                                                                          80       0        0     0      0     0                                        40       0        0     0      0     0                                  ______________________________________                                         Note:                                                                         *.sup.(1) Compound disclosed in Japanese Patent Publication (unexamined)      No. 88228/1973:                                                               ##STR16##                                                                     *.sup. (2) Compound disclosed in U.S. Pat. No. 3,498,781:                     ##STR17##                                                                     *.sup.(3) Compound disclosed in J. Am. Chem. Soc., 55, 4209 (1933):           ##STR18##                                                                     *.sup.(4) Compound disclosed in Japanese Patent Publication (unexamined)      No. 5005/1979:                                                                ##STR19##                                                                     *.sup.(5) Compound disclosed in Japanese Patent Publication (unexamined)      No. 5005/1979:                                                                ##STR20##                                                                

What is claimed is:
 1. A compound of the formula: ##STR21## wherein X isa hydrogen atom, a methyl group, a methoxy group or a chlorine atom, R₁is a C₂ -C₇ alkyl group or a C₅ -C₇ cycloalkyl group and R₂ is ahydrogen atom, a halogen atom, a C₁ -C₄ alkyl group or a methoxy group,or when R₁ and R₂ are taken together, they represent a C₄ -C₆ alkylenegroup, provided that when R₁ is a tertiary alkyl group, R₂ does notrepresent a halogen atom.
 2. The compound according to claim 1, whereinX is a hydrogen atom or a methyl group, R₁ is an isopropyl group or atert-butyl group and R₂ is a hydrogen atom, a methyl group, an ethylgroup, an n-propyl group or an isopropyl group.
 3. The compoundaccording to claim 1, wherein X is a hydrogen atom or a methyl group, R₁is an isopropyl group and R₂ is a bromine atom.
 4. The compoundaccording to claim 1, which is ##STR22##
 5. The compound according toclaim 1, which is ##STR23##
 6. The compound according to claim 1, whichis ##STR24##
 7. The compound according to claim 1, which is ##STR25## 8.The compound according to claim 1, which is ##STR26##
 9. The compoundaccording to claim 1, which is ##STR27##
 10. The compound according toclaim 1, which is ##STR28##
 11. The compound according to claim 1, whichis ##STR29##
 12. A herbicidal composition comprising an inert carrier ordiluent and a herbicidally effective amount of at least one of theN-dimethylbenzylacetamide derivatives according to claim 1 as an activeingredient.
 13. The composition according to claim 12, wherein saidcomposition further comprises one or more additional insecticides,fungicides, nematocides, mitocides, herbicides, plant growth regulators,acaricides or fertilizers.
 14. A method for controlling weeds whichcomprises contacting the weeds with a herbicidally effective amount ofat least one of the N-dimethylbenzylacetamide derivatives according toclaim 1.